Abstract: A method for producing a particle, containing a step of heating a mixture containing TiH2 and TiO2 at 700 to 950° C., wherein a molar ratio of the TiH2 to the TiO2 contained in the mixture is 5.0 to 6.8.

Abstract: Provided are oxide composite particles to be mixed with a resin to obtain a resin composition having high thermal conductivity, low dielectric constant, and low dielectric loss tangent. The oxide composite particles containing silica and alumina, in which the oxide composite particles contain 40 to 85% by mass of an ?-cristobalite crystal phase, 5 to 50% by mass of an ?-alumina crystal phase, and 10% by mass or less of a mullite crystal phase, and an elemental ratio of aluminum to silicon (aluminum/silicon) as determined by X-ray photoelectron spectroscopy is 1.5 or more.

Abstract: Oxide powder, of which a resin composition is obtained by mixing with a resin exhibits a low thermal expansion coefficient, high thermal conductivity and a low dielectric tangent. The oxide powder containing Ca, Al and Si; wherein the oxide powder contains 40% by mass or more of a crystal phase of high-temperature type cristobalite having Ca, Al and Si, based on the mass of the whole oxide powder; and wherein contents of Ca, Al and Si in the oxide powder are 1 to 5% by mole of CaO, 1 to 5% by mole of Al2O3 and 90 to 98% by mole of SiO2, respectively (the sum of contents of CaO, Al2O3 and SiO2 is 100% by mole) when converting the contents of Ca, Al and Si to contents of CaO, Al2O3 and SiO2.

Abstract: A method for producing a particle, containing a step of heating a mixture containing TiH2 and TiO2 at 700 to 900° C., wherein a molar ratio of the TiH2 to the TiO2 contained in the mixture is 3.1 to 4.6. A particle having a crystal composition composed of Ti2O3 and ?-Ti3O5, wherein a molar ratio of the Ti2O3 to the ?-Ti3O5 is 0.1 or more.

Abstract: A method for producing a composite particle, the method containing: (a) mixing a raw material particle and at least one type of fine particles selected from SiO2 fine particles and Al2O3 fine particles, the fine paricles having a diameter smaller than that of the raw material particle; and (b) heating the mixture of the raw material particles and the fine particles, wherein the raw material particle contains three components of ZnO, Al2O3, and SiO2, and a content of the ZnO is 17 to 43% by mole, a content of the Al2O3 is 9 to 20% by mole, and a content of the SiO2 is 48 to 63% by mole, based on the total content of the three components.

Abstract: A spherical silica powder which, when heated from 25° C. up to 1000° C. at a rate of 30° C./min, desorbs water molecules in an amount of 0.01 mmol/g or less at 500° C. to 1000° C., and which has a specific surface area of 1 to 30 m2/g.

Abstract: A spherical silica powder with a low dielectric tangent, wherein after formulating the spherical silica powder in a resin and molding it into a sheet, in a dielectric tangent of the spherical silica powder calculated by using he following Formula (I) based on a dielectric tangent (tan ?c) of the sheet which is measured under the conditions a frequency is 35-40 GHz with a resonator method, B/A is 0.70 or lower, wherein “A” represents a dielectric tangent (tan ?fA) of the spherical silica powder before a dielectric tangent reduction treatment and “B” represents a dielectric tangent (tan ?fB) of the spherical silica powder after a dielectric tangent reduction treatment; and a specific surface area of said spherical silica powder after a dielectric tangent reduction treatment is 1-30 m2/g.

Abstract: One aspect of the present invention provides a powder containing three components of ZnO, Al2O3 and SiO2, wherein each content of the three components is ZnO: 17 to 43% by mole, Al2O3: 9 to 20% by mole and SiO2: 48 to 63% by mole, based on the sum of the contents of the three components.

Abstract: Provided is a spherical alumina powder which, when incorporated into resins in a high concentration, enables a resin composition to have low viscosity and which has reduced viscosity increase in the resin composition over time after surface treatment of the spherical alumina powder. The spherical alumina powder has an alkyl group(s) derived from a silane compound(s) on its surface, and is characterized in that an intensity ratio {I (CH3)/I (CH2)} of a peak (2960±5 cm?1) associated with asymmetric vibration of CH3 to a peak (2925±5 cm?1) associated with asymmetric vibration of CH2 in the alkyl group(s) of the silane compound(s) in the same spectral data obtained by infrared spectroscopic analysis measurement is 0.2 or more and less than 2.0.

Abstract: Provided is a spherical alumina powder which, when incorporated into resins in a high concentration, enables a resin composition to have low viscosity and which has reduced viscosity increase in the resin composition over time after surface treatment of the spherical alumina powder. The spherical alumina powder has an alkyl group(s) derived from a silane compound(s) on its surface, and is characterized in that an intensity ratio {I (CH3)/I (CH2)} of a peak (2960±5 cm?1) associated with asymmetric vibration of CH3 to a peak (2925±5 cm?1) associated with asymmetric vibration of CH2 in the alkyl group(s) of the silane compound(s) in the same spectral data obtained by infrared spectroscopic analysis measurement is 0.2 or more and less than 2.0.

Abstract: The present invention is to provide hollow particles with a low degree of agglomeration and having a high roundness, and a process for producing them. Hollow particles comprising a silicon compound, having an average particle size of from 5 to 65 nm and an average roundness of at least 0.90, and having a shell comprising the silicon compound and having a thickness of from 1 to 20 nm. Further, a method for producing hollow particles, which comprises adding sulfuric acid to a liquid containing spherical organic polymer-silicon compound composite particles having a core comprising an organic polymer and a shell comprising a silicon compound in a medium containing at least 95 mass % of water, followed by heating to carbonize the organic polymer thereby to convert it to a carbide, and subjecting the carbide to decomposition using a liquid oxidizing agent other than sulfuric acid.

Abstract: Provided are a process for producing a highly reliable ceramic sheet with stable quality by reducing voids, and a ceramic substrate using the sheet. A highly reliable ceramic sheet with stable quality is obtained by using hydroxypropylmethyl cellulose as an organic binder, kneading a powder material, preferably, with a twin screw extruder, and then forming a sheet by means of a single screw extruder equipped with a sheet die, and the sheet is suitably used for a ceramic substrate and a ceramic circuit board.

Abstract: The present invention is to provide hollow particles with a low degree of agglomeration and having a high roundness, and a process for producing them. Hollow particles comprising a silicon compound, having an average particle size of from 5 to 65 nm and an average roundness of at least 0.90, and having a shell comprising the silicon compound and having a thickness of from 1 to 20 nm. Further, a method for producing hollow particles, which comprises adding sulfuric acid to a liquid containing spherical organic polymer-silicon compound composite particles having a core comprising an organic polymer and a shell comprising a silicon compound in a medium containing at least 95 mass % of water, followed by heating to carbonize the organic polymer thereby to convert it to a carbide, and subjecting the carbide to decomposition using a liquid oxidizing agent other than sulfuric acid.

Abstract: An organic polymer-silicon compound composite particle comprising (a) a core composed of an organic polymer particle containing polyvinyl acetate as a principal component and (b) a shell containing a silicon compound, an average particle size of the organic polymer-silicon compound composite particle being 5 to 150 nm.

Abstract: Provided are a silicon nitride substrate and a silicon nitride circuit board with excellent electrical characteristics, and power control parts utilizing them. A silicon nitride substrate comprises a silicon nitride sintered body obtainable by sintering a silicon nitride powder in the presence of a sintering aid comprising MgO, Y2O3 and SiO2 in a proportion of (1) MgO/(MgO+SiO2)=34-59 mol %, and (2) Y2O3/(Y2O3+SiO2)=50-66 mol %, and a silicon nitride circuit board utilizes it.

Abstract: The present invention is to provide hollow particles with a low degree of agglomeration and having a high roundness, and a process for producing them. Hollow particles comprising a silicon compound, having an average particle size of from 5 to 65 nm and an average roundness of at least 0.90, and having a shell comprising the silicon compound and having a thickness of from 1 to 20 nm. Further, a method for producing hollow particles, which comprises adding sulfuric acid to a liquid containing spherical organic polymer-silicon compound composite particles having a core comprising an organic polymer and a shell comprising a silicon compound in a medium containing at least 95 mass % of water, followed by heating to carbonize the organic polymer thereby to convert it to a carbide, and subjecting the carbide to decomposition using a liquid oxidizing agent other than sulfuric acid.

Abstract: Provided are a silicon nitride substrate and a silicon nitride circuit board with excellent electrical characteristics, and power control parts utilizing them. A silicon nitride substrate comprises a silicon nitride sintered body obtainable by sintering a silicon nitride powder in the presence of a sintering aid comprising MgO, Y2O3 and SiO2 in a proportion of (1) MgO/(MgO+SiO2)=34-59 mol %, and (2) Y2O3/(Y2O3+SiO2)=50-66 mol %, and a silicon nitride circuit board utilizes it.

Abstract: Provided are a process for producing a highly reliable ceramic sheet with stable quality by reducing voids, and a ceramic substrate using the sheet. A highly reliable ceramic sheet with stable quality is obtained by using hydroxypropylmethyl cellulose as an organic binder, kneading a powder material, preferably, with a twin screw extruder, and then forming a sheet by means of a single screw extruder equipped with a sheet die, and the sheet is suitably used for a ceramic substrate and a ceramic circuit board.